Raspberry Ketone

Chemical properties

It appears as white needle crystal or granular solid, exhibiting raspberry aroma and fruit aroma. The melting point temperature is 82~83 °C. It is insoluble in water and oil, being soluble in alcohol, ether and volatile oil.
The natural products exist in raspberry (raspberry) and so on.

Uses

1. Raspberry Ketone is used in the preparation of food spices with sweetening effect, can also be used for cosmetics and soap flavor.
2. Raspberry Ketone is widely used in strawberry, raspberry, pineapple, peaches and other food flavors, usually used as a fixing agent in the fruity flavor. In daily flavor, it can be used in formulations such as jasmine, gardenia flowers and tuberose. As a modifier, it can be used in jasmine, gardenia, tuberose and other fragrant daily flavor. In food flavors, it is mostly used for strawberries, pineapple, peaches, plums, mayberry and other fragrance. In medicine, it is mostly used as intermediates.

Production method

3.5mol 15% sodium hydroxide is first added to the reactor, and 2 mol of acetone and 1mol of p-hydroxybenzaldehyde are added dropwise under stirring. The temperature is controlled between 20 and 30 DEG C, and the stirring reaction is continued for 20 hours. The solid sodium salt of 4-p-hydroxyphenylbutene-3-ketone-2 was obtained after filtering, further dissolved in water, and then acidified with hydrochloric acid to precipitate 4-p-hydroxyphenylbutene-3-ketone-2, further filter and dry for further application.
The autoclave was supplied with 100 g of the intermediate and 5 g of the nickel catalyst, and the atmosphere was replaced with hydrogen. The mixture was heated to 120-140 °C and reacted at a pressure of 0.98 MPa for 1.5 h. After cooling, the catalyst was filtered off, the raspberry ketone content was 89% and the hydrogenation yield was 92%. The crude product above is subject to vacuum distillation once with further recrystallization of 1-2 times getting white crystals with the melting point of 82 ° C.
Phenol route
94g phenol and 85% phosphoric acid mixed catalyst were added into the reactor, 70g methyl vinyl ketone was added dropwise in 40min, the temperature was maintained at 15-20 ℃, and the reaction was stirred for 4h. After completion of the reaction, the reaction mixture was washed with water until neutral, and 63 g of phenol was distilled off under reduced pressure to obtain 25 g of a product having a melting point of 81.5 to 82.5 ° C and a yield of 80%.
It is obtained through the condensation between hydroxybenzaldehyde and acetone and further hydrogenation.
It is obtained through the condensation between the ketone acid and phenol.

Description

4-(p-Hydroxyphenyl)-2-butanone has a sweet, fruity, raspberry preserves odor. May be prepared by catalytic hydrogenation of phydroxy-benzylidene acetone in the presence of platinum black in ether or methanol or in the presence of palladium absorbed on charcoal.

Chemical Properties

4-(p-Hydroxyphenyl)-2-butanone has a sweet, fruity, raspberry preserves–type odor.

Chemical Properties

4-(4-Hydroxyphenyl)-2-butanone is a highly characteristic component of raspberry aroma. It forms colorless crystals (mp 82–83°C) with a sweet, fruity odor strongly reminiscent of raspberries. Raspberry ketone is prepared by alkali-catalyzed condensation of the alkali salt of 4-hydroxybenzaldehyde and acetone, followed by selective hydrogenation of the double bond in the resulting 4-hydroxybenzalacetone. Other syntheses start from phenol, which is converted into 4-(4-hydroxyphenyl)-2-butanone with methyl vinyl ketone or with 4-hydroxy-2-butanone.

Chemical Properties

white to slightly yellow powder or needles

Occurrence

Reported found European cranberry, raspberry, blackberry, loganberry and sea buckthorn (Hippophae rhamnoides L.).

Uses

4-(4-Hydroxyphenyl)-2-butanone is used in perfumery, in cosmetics, and as a food additive to impart a fruity odor.

Uses

The primary aroma compound of red raspberries, used in perfume compositions, shampoos, cosmetics and as a food additive. Also an impurity in the synthesis of Dobutamine (D494445).

Uses

Intermediates of Liquid Crystals

Definition

ChEBI: A ketone that is 4-phenylbutan-2-one in which the phenyl ring is substituted at position 4 by a hydroxy group. It is found in a variety of fruits including raspberries, blackberries and cranberries, and is used in perfumery and cosmetics.

Taste threshold values

Taste characteristics at 40 ppm: fruity, jamy, berry, raspberry, and blueberry with seedy, cotton candy nuances

Synthesis Reference(s)

The Journal of Organic Chemistry, 41, p. 1206, 1976 DOI: 10.1021/jo00869a026
Synthetic Communications, 19, p. 1109, 1989 DOI: 10.1080/00397918908051034

Flammability and Explosibility

Non flammable

Safety Profile

Poison by intraperitoneal route. Moderately toxic by ingestion. Flammable liquid. When heated to decomposition it emits acrid smoke and irritating fumes. See also KETONES.

Synthesis

1) from p-hydroxybenzaldehyde and acetone

Synthesized by Claisen -Schmidt condensation catalyzed by alkali, the process was optimized by orthogonal test to obtain 4 -p-hydroxyphenyl-3 -buten-2 -one (88.4% yield), and then continued to synthesize raspberry ketone by hydrogenation catalyzed by palladium charcoal (84.0% yield); NaOH solution was used as Claisen -Schmidt condensation NaOH solution was used as the Claisen -Schmidt condensation catalyst to synthesize p-hydroxyphenyl-3 -buten-2 -one, and then 5% Pd /C and nickel formate were used as the catalysts for the second step of the reaction, respectively, to obtain raspberry ketone in 72.55% and 65.7% yields, respectively.

The condensation reaction conditions of p-hydroxybenzaldehyde and acetone were investigated by orthogonal test, and the preferred process conditions were obtained as follows: material substance ratio n(p-hydroxybenzaldehyde)  n(acetone) n( NaOH) = 1.0  25  25 (reaction at 30 for 5 h), and then conventional hydrogenation-reduction, reduced-pressure distillation, and mixed-solvent recrystallization were obtained. Raspberry ketone (yield 61.8%); p-hydroxybenzaldehyde and acetone as raw materials, NaOH-catalyzed Claisen -Schmid condensation reaction, and then nickel formate as a catalyst, isopropanol as a solvent, hydrogenation reduction to produce raspberry ketone (yield 42.0%).

References

[1] Synlett, 2010, # 1, p. 93 - 96
[2] Applied Catalysis A: General, 2015, vol. 504, p. 654 - 663
[3] Journal of Organic Chemistry, 2016, vol. 81, # 9, p. 3528 - 3532
[4] Russian Journal of Organic Chemistry, 2001, vol. 37, # 11, p. 1534 - 1541
[5] Organic Process Research and Development, 2011, vol. 15, # 4, p. 858 - 870